最新刊期
      卷 42 ， 期 10 ， 2019

        ACCELERATOR, RAY TECHNOLOGY AND APPLICATIONS

      • LIU Fengqiong,LU Ziwei,ZHANG Hongbin,RONG Xinjuan,LI Ronghua,LI Haixia,LI Zhankui,WANG Xiuhua
        Vol. 42, Issue 10, (2019) DOI: 10.11889/j.0253-3219.2019.hjs.42.100201
        摘要：BackgroundCarbon stripping foil as a stripper is one of the important components of medical heavy ion accelerator. It is essential to develop the carbon stripping foil that meets the requirements of medical heavy ion accelerators.PurposeThis study aims to develop U-shaped carbon foil for medical heavy ion accelerator.MethodsAC carbon arc discharge method was employed to develop the carbon stripping foil, and its properties were measured by the methods of scanning electron microscopy (SEM) and Raman characterization. The “U-shaped” target frame was used to ensure that target frame did not affect the normal operation of ions in the injected ring. The edge of target frame was designed to be as narrow as 2 mm wide, and the effective area of the carbon stripping foil was 1 600 mm2 (40 mm × 40 mm).ResultsThe thickness of the carbon stripping foil is 15 μg·cm-2, and the thickness uniformity is 97.65%. The SEM test results show that the surface of the carbon stripping film is smooth and the internal structure is compact. The Raman test results show that the G peak near 1 580 cm-1 is stronger than the D peak located near 1 300 cm-1, indicating the degree of graphitization of the film is higher, and the 2D peak near 2 700 cm-1 is weak, indicating that the number of graphite molecules is higher.ConclusionThe carbon stripping foil developed in this study has a certain mechanical toughness thereby completing the automatic mold changing process of the carbon stripping foil.  
        关键词：Carbon stripping foil;“U-shaped” frame;Scanning electron microscopy;Raman characterization   
        317
        |
        22
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 1816075 false
        发布时间：2024-10-25
      • LIU Zhonghe,LI Zongchun,GUO Yinggang,HE Hua,ZHAO Wenbin
        Vol. 42, Issue 10, (2019) DOI: 10.11889/j.0253-3219.2019.hjs.42.100202
        摘要：BackgroundThe particle accelerator has a short downtime and requires high relative accuracy between magnets.PurposeThis study aims to improve the smoothing analysis efficiency of beam orbit by using moving least squares method.MethodsFirstly, the original smoothed data was preprocessed to make the ring magnet data linearly distributed. Secondly, the fitting area was meshed, the grid points were extracted and the appropriate basis function and weight function were selected. Then, three indicators of the smooth analysis were given and the whole calculation process was designed. Finally, the smoothing effects of the averaging method, the least squares fitting and iteration method and the method of this paper were compared and analyzed by simulation data.ResultsThe experimental results show that the fitting curve obtained by the method of this paper is the smoothest and the magnet adjustment times are the least under the same conditions.ConclusionsTo a certain extent, the adjustment time is saved and the adjustment efficiency is improved.  
        关键词：Moving least squares;Beam orbit;Smoothing analysis;Compact support domain   
        316
        |
        22
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 1816619 false
        发布时间：2024-10-25
      • YAN Longgang,CUI Yuzhu,ZHANG Hao,DENG Derong,LI Qing,ZHU Yingshun,YANG Xingfan,LI Ming
        Vol. 42, Issue 10, (2019) DOI: 10.11889/j.0253-3219.2019.hjs.42.100203
        摘要：BackgroundChina Academy of Engineering Physics THz Free electron laser (CAEP THz FEL), referred to as CTFEL, is the first scientific facility in China that can provide users with high power and wide-spectrum terahertz waves. As an accelerator-based radiation source, magnet is one of the most important components for the transportation, measurement and manipulation of electron bunch.PurposeThis study aims at the design and measurement of magnets to satisfy that requirements of CTFEL.MethodsAccording to the specifications of CTFEL magnets, the magnet system was designed to consist three solenoids, three 45° dipoles, one 90° dipole, six circular quadrupoles and six square quadrupoles. The problems of design and their solution schemes were described. The magnetic field distribution, integral field distribution, transverse field distribution and magnetic axis were measured.Results & ConclusionThe test results show that all magnets satisfied the specification requirements. At present, all magnets have been completely installed and commissioned to ensure the laser operation of the CTFEL facility.  
        关键词：CTFEL;Magnet;Structure design;Magnetic field measurement   
        314
        |
        19
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 1816089 false
        发布时间：2024-10-25
      • SHI Haoyu,WANG Qingbin,MA Zhongjian,DING Yadong
        Vol. 42, Issue 10, (2019) DOI: 10.11889/j.0253-3219.2019.hjs.42.100204
        摘要：BackgroundCircular electron positron collider (CEPC) is a high-energy accelerator, some beam produced by CEPC but not injected to energy intensifier need to be absorbed properly to keep the safety of the machine and the environment.PurposeThis study aims to design the beam dump, and give a process of design for the beam dumps used in high-energy accelerators.MethodsThe Monte-Carlo program FLUKA was employed for the preliminary design scheme of CEPC linac beam dump. As the basis of absorber design, different calculating methods of beam range was proposed and checked with Empirical formula.ResultsThe relationship between material selection of shield and overall shielding thickness is revealed. The introduction of variance reduction technique improves the accuracy of calculation results.ConclusionsThe empirical formula to estimate the stop range of electron is basically correct and same with the Monte-Carlo simulation. And the design itself is helpful to CEPC Project.  
        关键词：Radiation protection;Beam dump;Monte-Carlo method;CEPC   
        376
        |
        20
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 1816480 false
        发布时间：2024-10-25

        NUCLEAR CHEMISTRY, RADIOCHEMISTRY, RADIOPHARMACEUTICALS AND NUCLEAR MEDICINE

      • LI Zaisheng,HU Lingzhi,CHEN Qun
        Vol. 42, Issue 10, (2019) DOI: 10.11889/j.0253-3219.2019.hjs.42.100301
        摘要：BackgroundIntegrated positron emission tomography (PET) / magnetic resonance imaging (MRI) is a multimodal imaging system which can acquire PET and MRI images simultaneously. Due to the unique advantages in reflecting the anatomical structure and physiological function, PET/MRI has been widely commonly used in diagnosis of many brain diseases. Brain segmentation is of great significance to the quantitative study of brain images and the common method used in clinical diagnosis is atlas-based brain segmentation, which can be applied to both MRI images and PET images. Brain segmentation based on atlas for integrated PET/MRI image system only needs one modelity as the segmentation results can be mapped to another modelity.PurposeThis study aims to determine which modality should be used for atlas-based segmentation for high definition (HD) integrated PET/MRI image.MethodsComparative experiments with two image groups were designed and performed. In the first group, 150 PET images were registered to PET brain template to obtain brain segmentation. In the second group, 150 MRI images were registered to MRI brain template to obtain brain segmentation. Six regions were selected to calculate the dice value. Comparing the segmentation results of the two sets of images with their results based on first, the modality with a higher average dice value would be more suitable for atlas-based brain segmentation.ResultsIn PET group, the dice values of six regions were 0.62, 0.55, 0.63, 0.62, 0.71 and 0.69, respectively. In MRI group, the dice values of six regions were 0.68, 0.64, 0.79, 0.81, 0.77 and 0.79. The error coming from registering PET images to PET brain template was larger than that of registering MRI images to MRI brain template.ConclusionsPET-based segmentation accuracy is lower than MRI-based segmentation precision, hence the MRI image is more suitable for atlas-based brain segmentation.  
        关键词：PET/MRI;Registration;Segmentation;Brain template;Brain atlas   
        311
        |
        18
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 1816442 false
        发布时间：2024-10-25

        NUCLEAR ELECTRONICS AND INSTRUMENTATION

      • XIE Xicheng,ZHANG Yuanyuan,GUO Yajuan,LAI Wanchang
        Vol. 42, Issue 10, (2019) DOI: 10.11889/j.0253-3219.2019.hjs.42.100401
        摘要：BackgroundMaterial level detection is a very important issue for the automatic control of thermal power. How to monitor the material and powder level has become an urgent problem for the thermal power plant.PurposeThis study aims to find out the best detection angle and switching point to provide theoretical guidance for instrument development and sensitivity improvement.MethodsFirst of all, Monte Carlo simulation was applied to the optimum design of the best detection angle for non-radioactive nuclear ash hopper level meter in the range of 0°~90°. Then the angle between the ash bucket wall and the horizontal plane for the optimum detection angle was determinated. Finally, a complete model of dust hopper and passive nuclear level gauge for electrostatic precipitator (ESP) was established, and the high and low switch points material level were by "second derivative method".ResultsWhen the angle between the probe and the horizontal line reaches 30°, the maximum energy flux is detected while the angle between the ash bucket wall and the horizontal plane is 61.224°. The absorption dose rate curve of material level meter with different fly ash height at 30° detection angle is obtained.ConclusionsThis study provides theoretical guidance for the development of non-radioactive nuclear ash hopper level meter instrument and improvement of sensitivity in thermal power plants.  
        关键词：Monte Carlo simulation;The best detect angle;Switching point;Passive nuclear ash bucket level meter   
        317
        |
        20
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 1816124 false
        发布时间：2024-10-25
      • YANG Cuiping,XIN Jie,ZHOU Dongdong,LI Yiqiu,CHAI Lin,YOU Simei,ZHANG Baoguo,WEN Wanxin,ZHANG Ming,WANG Rensheng
        Vol. 42, Issue 10, (2019) DOI: 10.11889/j.0253-3219.2019.hjs.42.100402
        摘要：BackgroundA real-time, high position resolved in-vivo dose measurement of critical health tissues and tumors is one of the most direct quality assurance (QA) tools in the radiotherapy. Plastic scintillator fiber dosimeters (PSFDs) have great advantages in dose verification due to its small size, good radiation resistance and good tissue equivalence.PurposeThis study aims to develop a plastic scintillation fiber dosimeter （PSFD） based on silicon photomultiplier (SiPM)， and investigate its performance in clinical applications.MethodsWith a stable LED pulse optical source, the leakage current of SiPM was measured by the picoammeter. Time stability and repeatability of the dosimeter, temperature response and the influence of the transmission fiber curvature on the SiPM leakage current were systematically studied. The dynamic range of the dosimeter was measured by using a small animal radiotherapy machine and LED pulse optical source.ResultsThe results show that the leakage current changes <1% when the dosimeter works continuously for 8 h at constant temperature of 20 ℃, and the leakage current changes <0.5% during 32 h of intermittent operation. When the temperature change is less than 0.5 ℃, or the transmission fiber radius of curvature is greater than 11 cm, the output current change is less than 1%. The linear dynamic range of the dosimeter measurement is 100~9 000 cGy∙min-1.ConclusionsThe developed dosimeter basically meets the accuracy requirements of the clinical dose verification.  
        关键词：Plastic scintillating fiber;SiPM;Stability;Dose response   
        326
        |
        21
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 1816576 false
        发布时间：2024-10-25
      • ZHANG Xiaodong,OUYANG Xiaoping,HE Junzhang,WEI Chen,WENG Xiufeng,TAN Xinjian,FU Zhuming
        Vol. 42, Issue 10, (2019) DOI: 10.11889/j.0253-3219.2019.hjs.42.100403
        摘要：BackgroundMicrochannel plate (MCP) is an electron multiplier device with an ultra-fast time response, which can be directly used for the detection of charged particles. The gain of MCP has a large influence on the properties of the neutron detector.PurposeThis study aims to investigate the gain of the MCP through theoretical simulation and experimental test.MethodsFirst of all,a sub-ns time-response neutron detector based on recoiled proton and MCP was developed for experimental test.The Monte Carlo method was used to simulate the number of secondary electrons generated by a single electron multiplying on a single microchannel, and the electron gain of a single-chip MCP at different voltages was calculated. Then, the gain characteristics of two MCPs were studied by alpha particle experiments.ResultsThe calculation results show that the theoretical gain of a single-chip MCP is consistent with the MCP factory inspection report. The experimental results show that when the supply voltage of each MCP is 800 V, the gain of double MCP is about 9.0×106.ConclusionsThe method clarified in the paper is reliable and feasible, and provides a new technical approach for the study of MCP gain. It also provides a theoretical basis for studying the performance of MCP neutron detectors.  
        关键词：Microchannel plate;Secondary electron;Gain;Monte Carlo method;α particle   
        335
        |
        28
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 1816658 false
        发布时间：2024-10-25
      • GAO Feng,QIAN Sen,NING Zhe,WANG Zhigang,MA Lishuang,ZHU Yao,CHEN Pengyu,YIN Shiyu,WANG Zhile
        Vol. 42, Issue 10, (2019) DOI: 10.11889/j.0253-3219.2019.hjs.42.100404
        摘要：BackgroundThere are two methods to test the single photoelectron spectra (SPE) performance of the photomultiplier tubes (PMT) and Silicon Photomultiplie (SiPMT) with either the charge-to-digital-converter (QDC) module or flash amplitude-to-digital-converter (FADC) module.PurposeThis study aims to investigate the difference of data acquisition between FADC and QDC for single photoelectron spectra (SPE) of photoelectric detector.MethodsSingle photoelectron spectra (SPE) of 20-inch PMTs of the same model, as well as SiPMT of same mode, were measured under the same testing conditions using FADC module and QDC module. Gain, signal events, detection efficiency, the ratio of peak to valley and energy resolution were compared in details.ResultsBoth QDC and FADC can be used as data acquisition tools for PMT SPE test, but each has its own advantages and disadvantages.ConclusionsAccording to the system’s specific demand for photoelectric detector, either of the two modules could be chosen.  
        关键词：Photomultiplier tubes;SiPMT;Single photoelectron spectra;Charge-to-digital-converter;Flash amplitude-to-digital-converter   
        341
        |
        23
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 1816221 false
        发布时间：2024-10-25

        NUCLEAR PHYSICS, INTERDISCIPLINARY RESEARCH

      • HE Liwen,TONG Lili,CAO Xuewu
        Vol. 42, Issue 10, (2019) DOI: 10.11889/j.0253-3219.2019.hjs.42.100501
        摘要：BackgroundDuring a severe nuclear reactor accident, the aerosol deposited in the containment may resuspend due to airflow disturbance. It would increase the source terms in the containment and may eventually result in an increase in source terms that are released into the environment.PurposeThis study aims to analyse the applicability of aerosol resuspension force balance models based on the STORM (Simplified Test Of Resuspension Mechanism) experiment.MethodsFirstly, the analytical model of the experiment was established, and then the influence of the disturbing force coefficient, the deposition surface roughness in the Wichner model and the micro-protrusions distance in Michael model on the deposition surface were studied. The applicability of the models was evaluated by comparison between models prediction results and the experimental measurements.&Results & ConclusionsAnalysis results show that the Wichner force balance model is more suitable for predicting the resuspension behavior in a wide range of disturbed airflow velocity with small aerosol particle size.  
        关键词：Resuspension;Force balance;Airflow disturbance   
        323
        |
        20
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 1816157 false
        发布时间：2024-10-25
      • HAN Zijie,ZHU Tonghua,LU Xinxin,AN Li
        Vol. 42, Issue 10, (2019) DOI: 10.11889/j.0253-3219.2019.hjs.42.100502
        摘要：Backgroundγ-ray of 277.6 keV needs to be measured in plutonium production pates experiment. Self-absorption effect of depleted uranium activated foils will affect the accuracy of the measuring results.PurposeThis study aims to correct the γ-ray self-absorption effect of the activation foils in the plutonium production rates experiment.MethodsFirst of all, plane source method and substance method were applied to MCNP (Monte Carlo N Particle Transport Code) to simulate the self-absorption theory, and results at various detection distance were obtained. Then experiments using 243Am plane radioactive source, depleted uranium foils and the HPGe detector were carried out to obtain self-absorption factors of 277.6 keV gamma-ray for depleted uranium activated foils with different thickness.ResultsThe deviation of these two methods for simulation calculation of self-absorption factor is less than 1.3% at detection distance of 9 cm. The deviation between experimental measurement and simulation computation is less than 2.5% for depleted uranium foils with different thickness.ConclusionThe reliability of theoretical simulation is proved by the verification between experiment and theory in this study. Hence the self-absorption correction factors of samples under different measurement models can be obtained by theoretical simulation in the plutonium production rates experiment.  
        关键词：Plane radioactive source method;Substance method;Self-absorption correcting factor   
        319
        |
        22
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 1816406 false
        发布时间：2024-10-25

        NUCLEAR ENERGY SCIENCE AND ENGINEERING

      • WANG Wen,FAN Huiqing,CAI Maoyuan,ZHAI Lifang,ZHANG Xiaochun
        Vol. 42, Issue 10, (2019) DOI: 10.11889/j.0253-3219.2019.hjs.42.100601
        摘要：BackgroundThe temperature of the bolt connecting structure is around 650 ℃ in the scram system of the thorium molten salt reactor-liquid fuel 1 (TMSR-LF1) and the connecting components include three kinds of material, which have different coefficients of thermal expansion. Thermal expansion during the heating process, from room temperature to 650 ℃, and creep in the long lifetime of reactor will affect the bolt pretension, which may touch the safety of the scram system.PurposeThis study aims to analyse the stress relaxation of the bolting structure, and assess structural safety for the scram system of TMSR-LF1.MethodsThe ANSYS program was employed for the mechanical analysis of the bolt connecting model. The stress analysis and creep stress-relaxation analysis of the structure under the combined action of bolting preload and thermal expansion were performed.ResultsThe high temperature creep of bolted structural materials and the variation of stress relaxation caused by the creep and its influence on the pre-tightening force of bolted connection structures are obtained for the whole lifetime of the reactor. And the evaluation of the bolt is completed under.ConclusionsAccording to American society of mechanical engineers (ASME) standard in coordinate with ASME-III-5-HBB rules for bolt mechanical analysis and safety evaluation, the connecting bolt structure designed for TMSR-LF1 is demonstrated safe and reliable in the whole lifetime.  
        关键词：High temperature creep;Stress relaxation;Bolt pretension;Mechanical analysis   
        319
        |
        25
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 1816292 false
        发布时间：2024-10-25
      • ZHU Lin,LIU Guanglei,LIU Jingjing
        Vol. 42, Issue 10, (2019) DOI: 10.11889/j.0253-3219.2019.hjs.42.100602
        摘要：BackgroundIt is very important to locate ruptured fuel assemblies rapidly and accurately not only for emergency core refueling, but also for shortening critical path of overhaul.PurposeThis study aims at location of fuel assemblies failure using the activity ratio of 134Cs and 137Cs.MethodsThe relationship between the ratio of 134Cs to 137Cs activity and fuel consumption in the fuel assembly was theoretically calculated, and the theoretical model was modified by ORIGEN software.Results & ConclusionsIt is found that the activity ratio of 134Cs to 137Cs increases with the increase of the burn-up, and decreases with the increase of fuel assembly enrichment. With the improved 134Cs to 137Cs activity ratio and burnup model, the burnup of damaged fuel assemblies at different enrichment levels in pressurized water reactor (PWR) nuclear power plants can be determined, and then the damaged fuel assemblies can be quickly located.  
        关键词：Burn-up;134Cs;137Cs;Fuel assembly   
        362
        |
        19
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 1816250 false
        发布时间：2024-10-25
      • “在流体力学领域，专家通过CFD模拟研究了环形通道内单相水的摩擦阻力系数，提出了新的计算公式，为解决偏心度对摩擦阻力影响问题提供解决方案。”
        PENG Jun
        Vol. 42, Issue 10, Article number: 100603(2019) DOI: 10.11889/j.0253-3219.2019.hjs.42.100603
        摘要：BackgroundEccentricity in the manufacture and assembly of nuclear fuel assemblies will affect the annular channel.PurposeThis study aims to investigate the characteristics of the single-phase flow in narrow annular channels.MethodsComputational fluid dynamics (CFD) simulation on single-phase flow friction characteristic in straight annuli channel with different width (h=0.775~1.742 mm, 0.69<ri/ro<0.86) in ranges of laminar flow (300<Re<1 800) and fully developed turbulent flow (104<Re<105) were carried out by commercial code FLUENT. The influence of different eccentricity (e=0.01~0.5) was also considered.ResultsThe results show that for laminar flow the simulated friction factors are completely agreed with that of the analytic solution. When the Reynolds number is in the range of 104~5×104, the Blausius correlation achieves more exact results with CFD; and while the Reynolds number is in the range of 5×104~105, the McAdams correlation gets more consistent results with CFD.ConclusionsBased on the above conclusions, proposed correlation f=0.257 5Re-0.23 can well predict in the whole Reynolds number in the range of 104~105. Furthermore, the friction factor is a function of eccentricity, a relatively weak function of width, and independent of the Reynolds number.  
        关键词：Annuli channel;Flow friction;Single phase;Eccentricity   
        308
        |
        19
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 1816525 false
        发布时间：2024-10-25
      • LI Zhongyang,WU Bin,YU Shengpeng,HAO Lijuan,SONG Jing,LONG Pengcheng,WU Yican
        Vol. 42, Issue 10, (2019) DOI: 10.11889/j.0253-3219.2019.hjs.42.100604
        摘要：BackgroundThe high-fidelity nuclear reactor model requires a large amount of computing resources and a high-performance computing platform. High-performance computing platforms are cumbersome to operate and are not conducive to designers, while the cloud platform has the characteristics of super large scale and easy to use, hence has good application value for neutronics calculation.PurposeThis study aims to establish a neutron computing cloud platform for users.MethodsCombined with cloud computing technology, a neutron computing cloud platform based on Software as a Service (SaaS) mode was designed and implemented. Neutronics computing functions and related databases were set up to run in the cloud to provide SaaS mode computing services for end users.ResultsUsers can use computing resources anytime and anywhere through the browsers to effectively improve the efficiency of neutronics calculation.ConclusionsThe cloud platform proposed in this paper can be used for general nuclear design computation.  
        关键词：SuperMC;Cloud computing;SaaS;Service   
        316
        |
        20
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 1816350 false
        发布时间：2024-10-25
      0